Vapor analysis systems are designed to detect and remove from further use consumer returned contaminated plastic Polyethylene Terephthalate (PET) refillable bottles, which may be used for soft drinks, water, and other beverages. In certain regions of the world, in particular, Latin America, soft drinks are sold to consumers in PET bottles with a deposit. Upon return, the PET bottles are washed and refilled. Prior to refilling, the bottles are inspected for consumer added contaminants using an automated inspection system. If a contaminant is detected, the bottle is automatically removed from the production line and destroyed. The non-contaminated bottles continue on to be washed, cleaned, and refilled.
Before returning the PET bottles for the deposit, consumers may use empty bottles for various purposes, such as storage of household products, gasoline, mineral spirits, or for storing other types of beverages. Detecting and rejecting contaminated bottles is thus very important for beverage/bottling companies, as sale of beverages in contaminated bottles may result in a bad experience for the user, or worse, health problems. This can result in reputational damage and lost business for the beverage/bottling companies.
Companies use so called “hydrocarbon sniffers” in their refilling lines to detect and reject contaminated bottles as they are moved along a conveyor before they are cleaned and refilled. Sniffers have used various technologies to detect contamination, including photo-ionization detection, chemiluminescence, and electron capture detection. One such system is described in U.S. Pat. No. 5,318,911, entitled “System for Sampling and Detecting the Presence of Compounds in Containers.” These systems work well for detecting certain levels of contamination; however, there is a need for detection systems that are capable of more sensitive detection, i.e. detecting lower levels of contamination than the above described detectors would not detect.
Mass spectrometer (“mass spectrometer”) technology was tested as a potential basis of for a more sensitive contamination detection system in the refillable PET bottles, but has generally been considered unreliable and prone to malfunction and excessive false reject levels. The problem with mass spectrometer technology is that it operates poorly in an industrial environment where highly concentrated NOx and hydrocarbon bottles contaminate and overwhelm these very sensitive detectors, causing them temporarily go “blind” and not be capable of testing. At the speed of the typical inspection conveyor line, when the mass spectrometer goes blind, it will miss 15 to 20 bottles or more before it is able to detect contaminates again. While more sensitive and able to better detect contaminates, mass spectrometer detection has proven to be inefficient in high volume production applications.